// Copyright (c) 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef NET_BASE_NETWORK_ACTIVITY_MONITOR_H_
#define NET_BASE_NETWORK_ACTIVITY_MONITOR_H_

#include <stdint.h>

#include "base/lazy_instance.h"
#include "base/macros.h"
#include "base/synchronization/lock.h"
#include "base/time/time.h"
#include "net/base/net_export.h"

namespace net {

namespace test {

    class NetworkActivityMonitorPeer;

} // namespace test

// NetworkActivityMonitor tracks network activity across all sockets and
// provides cumulative statistics about bytes sent to and received from
// the network. It uses a lock to ensure thread-safety.
//
// There are a few caveats:
//  * Bytes "sent" includes all send attempts and may include
//    some bytes which were actually never sent over the network.
//  * Bytes received includes only bytes actually received from the network,
//    and does not include any bytes read from the the cache.
//  * Network activity not initiated directly using chromium sockets won't
//    be reflected here (for instance DNS queries issued by getaddrinfo()).
class NET_EXPORT_PRIVATE NetworkActivityMonitor {
public:
    // Returns the singleton instance of the monitor.
    static NetworkActivityMonitor* GetInstance();

    void IncrementBytesReceived(uint64_t bytes_received);
    void IncrementBytesSent(uint64_t bytes_sent);

    uint64_t GetBytesReceived() const;
    uint64_t GetBytesSent() const;

    base::TimeDelta GetTimeSinceLastReceived() const;
    base::TimeDelta GetTimeSinceLastSent() const;

private:
    friend class test::NetworkActivityMonitorPeer;

    NetworkActivityMonitor();
    ~NetworkActivityMonitor();
    friend struct base::DefaultLazyInstanceTraits<NetworkActivityMonitor>;

    // Protects all the following members.
    mutable base::Lock lock_;

    uint64_t bytes_received_;
    uint64_t bytes_sent_;

    base::TimeTicks last_received_ticks_;
    base::TimeTicks last_sent_ticks_;

    DISALLOW_COPY_AND_ASSIGN(NetworkActivityMonitor);
};

} // namespace net

#endif // NET_BASE_NETWORK_ACTIVITY_MONITOR_H_
